Thin sections observed with optical microscope in polarized non-analysed light showing the lithology diversity, (a). Mudstone in the Visean Turbidite (sample G8), (b). Siltstone in the Early Ordovician rocks (sample G1), (c). Early Cambrian green sandstone (Marcory formation, sample H32), (d). Mudstone in the Early Ordovician rocks (sample G2), (e). Middle Cambrian fine-grained sandstone (sample H22), (f). Early Ordovician mudstone (sample G3).